Hydrogen can provide clean energy for powering automobiles as well as for cooking, space heating, heating hot water, and supplying power to absorption air conditioning and refrigeration units. In addition, unlike conventional electricity, it may be stored for later use. As currently envisioned, widespread use of hydrogen will require a significant infrastructure for the efficient distribution and use of this fuel. Costs of hydrogen generation may also be a factor in its widespread use.
Hydrogen may be produced by the electrolysis of water, a readily available and inexpensive feedstock, by passing an electric current through the water. A source of direct current electricity is connected to an anode and a cathode placed in contact with the water and hydrogen is generated at the cathode and oxygen is generated at the anode. A membrane is interposed between the anode and the cathode and hydrogen ions move across the membrane, where they combine with electrons to form hydrogen gas. The membrane must be durable enough to withstand the caustic environment of the electrolysis process as well as the physical stress of the sometimes violent production of hydrogen and oxygen gas. Waste heat is also generated in the process, which, if recovered, may result in an increase in the overall efficiency of the electrolytic process.
There are many sources of the electric energy needed to generate hydrogen by the process of electrolysis. Traditional sources include burning fossil fuels such as coal, petroleum derivatives, and natural gas and nuclear plants and non-traditional sources such as wind power and solar panels may also be used. The flexibility to utilize electricity generated by a variety of sources can provide greater reliability of hydrogen generation. Utilizing electricity to generate hydrogen can also provide a convenient storage medium which may be used to dampen time-dependent fluctuations in power supply and energy demand.